1. Field of the Invention
The present application relates to a method of and apparatus for clearing precipitation from windows. Embodiments of the invention relate to clearing precipitation from the windscreen of a vehicle.
2. Description of the Related Technology
The current windscreen wiper, invented by Mary Anderson, in 1903, has served the motorist well for almost a century, however, despite many improvements over the years, it has limitations such as a narrow field of view for driver and passenger, smearing, juddering, lifting at speed, scratching the windscreen surface and the vital need for renewal of the wiper blade. The driver's vision is even further impaired when driving at speed at night in heavy rain, especially with regard to oncoming vehicle headlights.
When it rains, water droplets, which normally cause the transmission of light through the windscreen to be distorted, make it virtually impossible to see the road clearly. The conventional windscreen wipers intermittently clear an area directly in front of the driver and passenger at controlled speeds; however in heavy rain, the driver has a clear view for only short periods as the wipers traverse the windscreen. This results in the driver effectively driving partially blind and could miss seeing a pedestrian or cyclist or another vehicle, especially at night.
Various prior proposals for using clearing precipitation using ultrasound are disclosed in, GB2387107 and U.S. Pat. No. 4,768,256 amongst other proposals. It is known from DE20 2004 019 608 U1 to provide ultrasonic transducers on windscreen wipers which move across a windscreen. It is known from GB1037787 to insonify ultrasound from the corners or edges of the windscreen where the transducers are not bonded or in a physical contact with the windscreen, which results in significant energy loss. As far as is known to the current applicants, no prior proposal using ultrasound has been put into practice.